package jjn.round1;

/**
 * @author Jiang Jining
 * @since 2023-04-27 23:44
 */
public class LeetCode63_UniquePathsV2 {
    public int uniquePathsWithObstacles(int[][] obstacleGrid) {
        // obstacleGrid[j][i] == 1, 有障碍
        if (obstacleGrid == null || obstacleGrid.length == 0) {
            return 0;
        }
        if (obstacleGrid[0][0] == 1) {
            return 0;
        }
        int height = obstacleGrid.length;
        int width = obstacleGrid[0].length;
        int[][] dp = new int[height][width];
        for (int i = 0; i < height; i++) {
            if (obstacleGrid[i][0] == 0) {
                dp[i][0] = 1;
            } else {
                break;
            }
        }
        for (int i = 0; i < width; i++) {
            if (obstacleGrid[0][i] == 0) {
                dp[0][i] = 1;
            } else {
                break;
            }
        }
        for (int i = 1; i < height; i++) {
            for (int j = 1; j < width; j++) {
                if (obstacleGrid[i][j] == 0) {
                    dp[i][j] = dp[i - 1][j] + dp[i][j - 1];
                }
            }
        }
        return dp[height - 1][width - 1];
    }
}
